gstreamer/gst/autoplug/gstautoplugcache.c

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/* GStreamer
* Copyright (C) 2001 RidgeRun, Inc. (www.ridgerun.com)
*
* gstautoplugcache.c: Data cache for the dynamic autoplugger
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include <gst/gst.h>
GstElementDetails gst_autoplugcache_details = {
"AutoplugCache",
"Connection",
"Data cache for the dynamic autoplugger",
VERSION,
"Erik Walthinsen <omega@temple-baptist.com>",
"(C) 2001 RidgeRun, Inc. (www.ridgerun.com)",
};
#define GST_TYPE_AUTOPLUGCACHE \
(gst_autoplugcache_get_type())
#define GST_AUTOPLUGCACHE(obj) \
(GTK_CHECK_CAST((obj),GST_TYPE_AUTOPLUGCACHE,GstAutoplugCache))
#define GST_AUTOPLUGCACHE_CLASS(klass) \
(GTK_CHECK_CLASS_CAST((klass),GST_TYPE_AUTOPLUGCACHE,GstAutoplugCacheClass))
#define GST_IS_AUTOPLUGCACHE(obj) \
(GTK_CHECK_TYPE((obj),GST_TYPE_AUTOPLUGCACHE))
#define GST_IS_AUTOPLUGCACHE_CLASS(obj) \
(GTK_CHECK_CLASS_TYPE((klass),GST_TYPE_AUTOPLUGCACHE))
typedef struct _GstAutoplugCache GstAutoplugCache;
typedef struct _GstAutoplugCacheClass GstAutoplugCacheClass;
struct _GstAutoplugCache {
GstElement element;
GstPad *sinkpad, *srcpad;
GList *cache;
GList *cache_start;
gint buffer_count;
GList *current_playout;
gboolean fire_empty;
};
struct _GstAutoplugCacheClass {
GstElementClass parent_class;
void (*cache_empty) (GstElement *element);
};
/* Cache signals and args */
enum {
CACHE_EMPTY,
LAST_SIGNAL
};
enum {
ARG_0,
ARG_BUFFER_COUNT,
ARG_RESET
};
static void gst_autoplugcache_class_init (GstAutoplugCacheClass *klass);
static void gst_autoplugcache_init (GstAutoplugCache *cache);
static void gst_autoplugcache_set_arg (GtkObject *object, GtkArg *arg, guint id);
static void gst_autoplugcache_get_arg (GtkObject *object, GtkArg *arg, guint id);
static void gst_autoplugcache_loop (GstElement *element);
static GstPadNegotiateReturn gst_autoplugcache_nego_src (GstPad *pad, GstCaps **caps, gpointer *data);
static GstPadNegotiateReturn gst_autoplugcache_nego_sink (GstPad *pad, GstCaps **caps, gpointer *data);
static GstElementStateReturn gst_autoplugcache_change_state (GstElement *element);
static GstElementClass *parent_class = NULL;
static guint gst_autoplugcache_signals[LAST_SIGNAL] = { 0 };
GtkType
gst_autoplugcache_get_type(void) {
static GtkType autoplugcache_type = 0;
if (!autoplugcache_type) {
static const GtkTypeInfo autoplugcache_info = {
"GstAutoplugCache",
sizeof(GstAutoplugCache),
sizeof(GstAutoplugCacheClass),
(GtkClassInitFunc)gst_autoplugcache_class_init,
(GtkObjectInitFunc)gst_autoplugcache_init,
(GtkArgSetFunc)gst_autoplugcache_set_arg,
(GtkArgGetFunc)gst_autoplugcache_get_arg,
(GtkClassInitFunc)NULL,
};
autoplugcache_type = gtk_type_unique (GST_TYPE_ELEMENT, &autoplugcache_info);
}
return autoplugcache_type;
}
static void
gst_autoplugcache_class_init (GstAutoplugCacheClass *klass)
{
GtkObjectClass *gtkobject_class;
GstElementClass *gstelement_class;
gtkobject_class = (GtkObjectClass*)klass;
gstelement_class = (GstElementClass*)klass;
parent_class = gtk_type_class (GST_TYPE_ELEMENT);
gst_autoplugcache_signals[CACHE_EMPTY] =
gtk_signal_new ("cache_empty", GTK_RUN_LAST, gtkobject_class->type,
GTK_SIGNAL_OFFSET (GstAutoplugCacheClass, cache_empty),
gtk_marshal_NONE__NONE, GTK_TYPE_NONE, 0);
gtk_object_class_add_signals (gtkobject_class, gst_autoplugcache_signals, LAST_SIGNAL);
gtk_object_add_arg_type ("GstAutoplugCache::buffer_count", GTK_TYPE_INT,
GTK_ARG_READABLE, ARG_BUFFER_COUNT);
gtk_object_add_arg_type ("GstAutoplugCache::reset", GTK_TYPE_BOOL,
GTK_ARG_WRITABLE, ARG_RESET);
gtkobject_class->set_arg = gst_autoplugcache_set_arg;
gtkobject_class->get_arg = gst_autoplugcache_get_arg;
gstelement_class->change_state = gst_autoplugcache_change_state;
}
static void
gst_autoplugcache_init (GstAutoplugCache *cache)
{
gst_element_set_loop_function(GST_ELEMENT(cache), GST_DEBUG_FUNCPTR(gst_autoplugcache_loop));
cache->sinkpad = gst_pad_new ("sink", GST_PAD_SINK);
gst_pad_set_negotiate_function (cache->sinkpad, gst_autoplugcache_nego_sink);
gst_element_add_pad (GST_ELEMENT(cache), cache->sinkpad);
cache->srcpad = gst_pad_new ("src", GST_PAD_SRC);
gst_pad_set_negotiate_function (cache->sinkpad, gst_autoplugcache_nego_src);
gst_element_add_pad (GST_ELEMENT(cache), cache->srcpad);
// provide a zero basis for the cache
cache->cache = g_list_prepend(NULL, NULL);
cache->cache_start = cache->cache;
cache->buffer_count = 0;
cache->current_playout = 0;
cache->fire_empty = FALSE;
}
static void
gst_autoplugcache_loop (GstElement *element)
{
GstAutoplugCache *cache;
GstBuffer *buf;
cache = GST_AUTOPLUGCACHE (element);
/* Theory:
* The cache is a doubly-linked list. The front of the list is the most recent
* buffer, the end of the list is the first buffer. The playout pointer always
* points to the latest buffer sent out the end. cache points to the front
* (most reccent) of the list at all times. cache_start points to the first
* buffer, i.e. the end of the list.
* If the playout pointer does not have a prev (towards the most recent) buffer
* (== NULL), a buffer must be pulled from the sink pad and added to the cache.
* When the playout pointer gets reset (as in a set_arg), the cache is walked
* without problems, because the playout pointer has a non-NULL next. When
* the playout pointer hits the end of cache again it has to start pulling.
*/
do {
// the first time through, the current_playout pointer is going to be NULL
if (cache->current_playout == NULL) {
// get a buffer
buf = gst_pad_pull (cache->sinkpad);
// add it to the cache, though cache == NULL
gst_buffer_ref (buf);
cache->cache = g_list_prepend (cache->cache, buf);
cache->buffer_count++;
// set the current_playout pointer
cache->current_playout = cache->cache;
// send the buffer on its way
gst_pad_push (cache->srcpad, buf);
}
// the steady state is where the playout is at the front of the cache
else if (g_list_previous(cache->current_playout) == NULL) {
// if we've been told to fire an empty signal (after a reset)
if (cache->fire_empty) {
int oldstate = GST_STATE(cache);
fprintf(stderr,"at front of cache, about to pull, but firing signal\n");
gtk_signal_emit (GTK_OBJECT(cache), gst_autoplugcache_signals[CACHE_EMPTY], NULL);
if (GST_STATE(cache) != oldstate) {
GST_DEBUG(GST_CAT_AUTOPLUG, "state changed during signal, aborting\n");
cothread_switch(cothread_current_main());
}
}
// get a buffer
buf = gst_pad_pull (cache->sinkpad);
// add it to the front of the cache
gst_buffer_ref (buf);
cache->cache = g_list_prepend (cache->cache, buf);
cache->buffer_count++;
// set the current_playout pointer
cache->current_playout = cache->cache;
// send the buffer on its way
gst_pad_push (cache->srcpad, buf);
}
// otherwise we're trundling through existing cached buffers
else {
// move the current_playout pointer
cache->current_playout = g_list_previous (cache->current_playout);
// push that buffer
gst_pad_push (cache->srcpad, GST_BUFFER(cache->current_playout->data));
}
} while (!GST_FLAG_IS_SET (element, GST_ELEMENT_COTHREAD_STOPPING));
}
static GstPadNegotiateReturn
gst_autoplugcache_nego_src (GstPad *pad, GstCaps **caps, gpointer *data)
{
GstAutoplugCache *cache = GST_AUTOPLUGCACHE (GST_PAD_PARENT (pad));
return gst_pad_negotiate_proxy (pad, cache->sinkpad, caps);
}
static GstPadNegotiateReturn
gst_autoplugcache_nego_sink (GstPad *pad, GstCaps **caps, gpointer *data)
{
GstAutoplugCache *cache = GST_AUTOPLUGCACHE (GST_PAD_PARENT (pad));
return gst_pad_negotiate_proxy (pad, cache->srcpad, caps);
}
static GstElementStateReturn
gst_autoplugcache_change_state (GstElement *element)
{
// FIXME this should do something like free the cache on ->NULL
if (GST_ELEMENT_CLASS (parent_class)->change_state)
return GST_ELEMENT_CLASS (parent_class)->change_state (element);
return GST_STATE_SUCCESS;
}
static void
gst_autoplugcache_set_arg (GtkObject *object, GtkArg *arg, guint id)
{
GstAutoplugCache *cache;
cache = GST_AUTOPLUGCACHE (object);
switch (id) {
case ARG_RESET:
// no idea why anyone would set this to FALSE, but just in case ;-)
if (GTK_VALUE_BOOL(*arg)) {
fprintf(stderr,"resetting playout pointer\n");
// reset the playout pointer to the begining again
cache->current_playout = cache->cache_start;
// now we can fire a signal when the cache runs dry
cache->fire_empty = TRUE;
}
break;
default:
break;
}
}
static void
gst_autoplugcache_get_arg (GtkObject *object, GtkArg *arg, guint id)
{
GstAutoplugCache *cache;
cache = GST_AUTOPLUGCACHE (object);
switch (id) {
case ARG_BUFFER_COUNT:
GTK_VALUE_INT(*arg) = cache->buffer_count;
break;
default:
arg->type = GTK_TYPE_INVALID;
break;
}
}
static gboolean
plugin_init (GModule *module, GstPlugin *plugin)
{
GstElementFactory *factory;
factory = gst_elementfactory_new ("autoplugcache", GST_TYPE_AUTOPLUGCACHE,
&gst_autoplugcache_details);
g_return_val_if_fail (factory != NULL, FALSE);
gst_plugin_add_factory (plugin, factory);
return TRUE;
}
GstPluginDesc plugin_desc = {
GST_VERSION_MAJOR,
GST_VERSION_MINOR,
"autoplugcache",
plugin_init
};